Method and apparatus for purifying combustion gases

ABSTRACT

Waste combustion or exhaust gases from an internal combustion engine for motor vehicle or from other sources are directed into intimate, direct contact with the surface of ice which is supported by a subsurface and which presents an extended area of ice surface for travel of the combustion gases in contact therewith for accomplishing the deposition of particulate and other pollutants on the moist ice surface thereby provided. A moist sludge containing the pollutants is sloughed off of the ice surface and is collected, thereby separating the pollutants from residual combustion gases. As a result of passing residual combustion gases over the surface of the collected sludge unburned carbon contained therein is produced in a form having utility as a source of activated carbon and of carbon black.

a V f E 3. U te States atent 1 [111 3,748,830 Ross et ai. 5] July 31,1973 METHOD AND APPARATUS FOR 3,678,657 7 1972 Hale 55 010.

PURIFYING COMBUSTION GASES [75 Inventors: Sigmund L. Ross, Bronx PrimaryExaminerBemard Nozick Oscar Shuffman, Scarsdale, both Attorney-Thomas M.Marshall of N.Y.

[73] Assignee: Said Oscar Shuffman by Sigmund L. Ross [57] ABSTRACT [22]d, Ma 19 7 Waste combustion or exhaust gases from an internal ycombustion engine for motor vehicle or from other [21] Appl. No.:255,001 sources are directed into intimate, direct contact with ReatedApplication Data the surface of ice which is supported by a subsurfaceand which presents an extended area of ice surface for [63]continuation'in'pan travel of the combustion gases in contact therewithfor l97l, abandoned, which is a continuation-in-part of accomplishingthe deposition of particulate and other June 1970 abandoned' pollutantson the moist ice surface thereby provided. A

[52] U S Cl 55/89 55/222 55/228 moist sludge containing the pollutantsis sloughed off of 55/259 55/269 55/276 SS/DIG 30 /310 the ice surfaceand is collected, thereby separating the 60/517 60/520 62/3'23 3pollutants from residual combustion gases. As a result of passingresidual combustion gases over the surface g of the collected sludgeunburned carbon contained therein is produced in a form having utilityas a source 55/259 60/310 6 of activated carbon and of carbon black.

[56] References Cited 26 Claims, 22 Drawing Figures UNITED STATESPATENTS 3,153,579 10/1964 Levey et al. 55/DIG. 3O

Pmmemum ma 3.748.880

SHEET 1 0F 6 RECEIVER I5 I l SUCTION {11: VALVE COMPRESSZE CONDENSER F IG I r 13 l at WM '1 E APO ATOR. 5 r

2? v l7 I8 I @EXP. 2 v 23 2 VALVE 8 39 25 PURGED Enema l l l l l l lfiHAS EXHAUST MUFFLER 20 1 A CHAMBER 49 45 ICE CONTACT CHAN I SLUDGECOLLECTICNI CHAMBER PAIENIED JUL3 1 I975 SHEEF 2 OF 6 PATENIEDJUL31 maSHEEI 5 0F 6 t; BAGS 535$ mwwzmozou METHOD AND APPARATUS FOR PURIFYINGCOMBUSTION GASES This is a continuation-in-part application ofapplication Ser. No. l31,037 filed Apr. 5, 1971 for METHOD AND APPARATUSFOR PURIFYING COMBUS- TlON GASES in the name of SIGMUND L. ROSS ANDOSCAR SHUFFMAN. Said US. application Ser. No. 131,037 is acontinuation-in-part of application Ser. No. 42,622 filed June 2, 1970by the same inventors both abandoned.

This invention relates to the removal of atmospheric pollutants fromwaste combustion gases and the recovery of useful products therefrom.The invention is of particular utility as a pollution control device forinstallation on vehicles propelled by an internal combustion engine.

Internal combustion engines employed in motor vehicles are a principalsource of atmospheric pollution. The pollutants occur in a variety ofdifferent forms. Thus, one of the pollutants is in the form of unburnedcarbon particles. The direct products of combustion include carbondioxide, carbon monoxide and water. Carbon dioxide is harmless butcarbon monoxide has known toxic properties. Another major pollutant isthe sulfur dioxide that is contained in waste combustion gases. Inaddition, there are other pollutants such as oxides of nitrogen, leadcompounds, aldehydes, irritant gases and a variety of unburned petroleumhydrocarbons. There is an urgent need for the removal of or reduction inthe amount of noxious pollutants in waste combustion gases. To this endmany proposals have been offered. Thus it has been proposed to chillproducts of combustion passing through the exhaust pipe of an internalcombustion engine for an automobile sufficiently to condense unburnedhydrocarbons and any water vapor contained in the products ofcombustion. However, the only reduction in pollutant content is thatwhich is afforded by the condensation of unburned hydrocarbons. Theremoved unburned hydrocarbons are separated from the condensed water andare returned to the intake of the engine. The separated water is bledout of the system. In a system of this type the bulk of the pollutantsother than the unburned hydrocarbons emerge from the tail pipe. It alsohas been proposed to employ chemical reagents employed in an aqueousmedium, the aqueous chemical reagents being recircu lated into contactwith the exhaust gases. However, the chemical reagents have to bereplenished and their efflcacy is questionable. It also has beenproposed to employ catalysts to induce chemical reactions which tend todiminish the content of pollutants. However, such catalysts are specificto specific pollutants and have not proved to be sufficiently effectiveto go into commercial use. While these and other proposals have beenmade, the automotive industry is still seeking a practical and effectiveway of overcoming or minimizing the pollution problem presented by theexhaust of internal combustion engines used in motor vehicles.

The principal object of this invention is to effectively and bypractical means remove or greatly reduce the amount of atmosphericpollutants which occur in the exhausts of internal combustion engines orother waste combustion gases.

it is a further object of this invention to remove the objectionablepollutants in a form that is useful by reason of its high content ofcarbon in a form having utiliity as a source of activated carbon and ofcarbon black.

In accordance with this invention, waste combustion gases are directedinto direct and intimate contact with the surface of ice in the mannerand with the effect on pollutants hereinafter described. This ordinarilyis accomplished by the provision in a confining chamber through whichexhaust gases are passed over a body of ice having an extended surfaceso that the gases while confined flow through an elongated zone oftravel in turbulent contact with the ice. Because of the occurence ofthe ice in this chamber the chamber in which the ice is formed isreferred to for brevity as the ice contact chamber. The body of ice maybe conveniently formed so as to provide an extended area of ice surfaceby the use of out-of-contact thermal exchange means which provide asubsurface on which the ice is formed and which may be disposed in anyconfiguration which may be desired. For example, the out-ofcontactthermal exchange means which presents the subsurface may be in the formof one or more coils of tubing through which a refrigerant is passed ata temperature sufficiently low to cause the condensation of moisture inthe combustion gases on the surface thereof and, in addition, thefreezing of the condensed moisture so as to form a substantial body ofice supported by the coils of the thermal exchange means. in order toassist in bringing the combustion gases into intimate turbulent contactwith the surface of the ice, successive baffles preferably are employedwhich direct the gases repeatedly into turbulent contacts with surfacesof the ice whereby the gases are more effectively scrubbed free ofpollutants by contact with the ice surface.

The scavenging effected by the scrubbing action of the ice has beenfound to be extremely effective. Gases such as sulfur dioxide, oxides ofnitrogen and carbon monoxide are effectively removed. Likewise lead saltresidues from tetraethyl lead. Solid particles also are removed,including more especially carbonaceous particles and likewise unburnedhydrocarbons and residues thereof. So far as is known, these resultshave not heretofore been obtained in a practically feasible manner.

The means for refrigerating the thermal exchange means may utilize theconventional air conditioning equipment which is used in many motorvehicles. In such case the conventional refrigerating equipment may beutilized both for the purpose of providing air conditioning for theinterior of the body of the motor vehicle and as providing a source ofrefrigerant for use in the exhaust gas purifying means of thisinvention.

While it may appear on first impression that the maintenance of a bodyof ice in the exhaust system of an internal combustion engine is farfetched from the standpoint of being something which might practicallybe done in the case of a conventional automobile, for example, it nowhas been found that this invention not only is effective but also iseconomical and practical. In fact, all that is required in order tomaintain the necessary refrigeration load is a compressor comparable tothe type of compressor conventionally employed for use in airconditioning a conventional air conditioned automobile, namely, acompressor of the order of onequarter or one-third horsepower.

It also is a feature and advantages of this invention that it lendsitself to utilization in the type of exhaust system of a conventionalautomobile either in conjection with a conventional muffler or as amuffler which has embodied therein the capability, pursuant to thisinvention, of a highly effective elimination of the pollutantsordinarily encountered in the exhaust gases of an internal combustionengine. Accordingly, this invention provides a practical solution of theproblem of removal of pollutants from the exhaust gases of the internalcombustion engine of an automobile with very little modification ofexisting equipment.

The present invention also is unique in that it provides a source ofuseful carbonaceous recovered material.

During the period immediately after starting the internal combustionengine of a motor vehicle, for example, the exhaust gases flow intodirect contact with the refrigerated surface of the thermal exchangemeans that is utilized according to our invention and, as aforesaid, themoisture content thereof condenses and freezes and builds up asubstantial body of ice on the surface of the thermal exchange meanswhich then becomes a subsurface for supporting the body of ice thatprovides the surface for contact with the exhaust gases during continuedoperation of the engine.

After the body of ice has been formed it has been found that the ice isextremely effective in causing the deposition of solid particles such asparticles of unburned carbon. This is highly significant for these arenecessary in providing freezing nuclei, for while liquid and gases canact as condensation nuclei in the atmosphere only solid particles serveas freezing nuclei for promoting the formation and buildup of ice toform the ice bed. The deposited particles coupled with the chillingeffect of the ice serves to condense additional moisture with thecreation of a condition wherein the condensed moisture in excess of thatwhich freezes in the form of ice sloughs off the ice surface, carryingwith it the particulate matter deposited on the ice surface. Moreover,the capacity to take up gaseous pollutants increases markedly as thetemperature is reduced and the sloughed off water which is at the lowtemperature of melting ice and the particulate matter serve in a highlyeffective manner in absorbing noxious gases and in taking up condensedliquids such as unburned hydrocarbons, salts and other compounds. Asused herein, the reference to gaseous pollutants includes unburnedhydrocarbons as well as gases such as sulfur dioxide and oxides ofnitrogen. The deposited material that is formed is in the nature of amoist sludge which as it continues to be formed gradually sloughs offthe surface of the ice and is of such nature that it is removable fromthe ice contact chamber. Such removal is ordinarily assisted by the flowof residual combustion gases through the ice contact chamber in a mannerwhich promotes gradual flow of the sludge out of the ice contact chamberand into a collection container.

The formation of the body of ice in the ice contact chamber comprised inthe refrigerant evaporation zone of the system is of critical importancein the practice of this invention. Whether the ice as formed iscontinuous or discontinuous is immaterial.so long as an extended area ofice surface is provided for establishing direct contact of the ice withthe exhaust gases and the exhaust gases are caused to flow in contactwith the ice surface through an elongated or extended zone of travelduring which the gases are subjected to continued scrubbing as theytravel along so as to enhance the effectiveness of the scavengingaction.

While this invention is not to be regarded as depen dent on thecorrectness of any theoretical considerations mentioned herein inexplanation of the effectiveness with which pollutants may be removedfrom waste combustion gases, the high degree of effectiveness of thisinvention in removing pollutants from exhaust gases involves thephenomenon that when ice is formed from freezing water it becomesnaturally endowed with an electrostatic charge. The moving stream ofexhaust gases as a result of its movement relative to the ice alsoacquires an electrostatic charge which is opposite to that of the ice,with the result that there is electrostatic attraction which promotesthe capture on the wet ice surface of suspended particulate matter. Theelectrostatic attraction is supplemented by the thermal precipitationeffect which is induced by the travel of the exhaust gases through azone where there is a temperature differential between the cold icesurface in contact with the gases and a zone of higher temperaturewherein the greater molecular activity by its directional bombardingdifferential urges the particulate matter toward the colder surface withincidental consolidation of attracted particles and droplets thatcontributes to their deposition on the ice surface. The attractiontoward and deposit on the ice surface also is assisted by turbulenceinduced by baffles with resultant enhanced ionization of the gases. Bycausing the exhaust gases to travel while confined through an elongatedzone of travel in contact with the surface of the ice, the aforesaidcombined influences are utilized and have a very high degree ofeffectiveness in thoroughly scrubbing and scavenging the variouspollutants from the exhaust gases. Furthermore, because the condensingwater vapor utilizes the suspended particulate matter as nuclei on whichto condense, because of the lowering of the temperature and thelessening of kinetic energy of the moving gas stream, and because of theoccurrence of the increase in particle weight caused by the condensationof water thereon the particulate matter attracted to and captured on theice surfaces eventually sloughs off assisted by the scrubbing anderoding action of the moving stream of the exhaust gases along thesurfaces of the body of melting ice. in addition, because dissolvedgases separate out of solution upon freezing with formation of bubbleinclusions in and on the ice and because dissolved salts tend toconcentrate at crystal boundaries, the combined action of capture andsloughing off of chemical as well as particulate pollutants is that of aconcentrator whereby the pollutants are caused to become concentrated inthe sludge. The result is the formation of a moist sludge which containsthe pollutants and which can readily be handled and stored for ultimatedisposal. More specifically, the sludge in the embodiment hereindisclosed reaches the bottom of the portion of the ice contact chamberwherein it is formed and becomes separated from the residual exhaustgases. The accumulating sludge also lends itself to being moved out ofthe ice contact cham her and its removal preferably is assisted bymoving the sludge out through an opening through which the residualexhaust gases are emitted so that the kinetic energy of the moving gaseswill increase the rate of removal of the sludge from the ice contactchamber.

As the particulate matter is captured and sloughed off the ice surfacein the form of a sludge the noxious gases and vapors entrained in theexhaust gases as the temperature of the exhaust gases becomes lowered asaforesaid become increasingly soluble in and miscible with thecondensing water vapor, and under the conditions prevailing in the icecontact chamber the removal of gaseous and vapor pollutants isaccomplished in a highly effective manner so as to be carried down withthe sludge and removed from the residual exhaust gases along with thesludge.

It is a further feature of this invention that the sludge which isformed in the ice contact chamber is removed into a collection containerwherein it is permitted to accumulate. When a sufficient amount ofaccumulated sludge has built up to warrant doing so, the accumulatedsludge may be removed from the collection container. This may be readilyaccomplished as by blowing it out of the collection container withcompressed air. The operation is a simple one which can be taken care ofwhenever necessary at a garage or service station.

It is a further feature of this invention that as the sludge graduallyaccumulates in the collection container the stream of residual exhaustgases is directed so as to sweep over the surface of the cool, dampsludge. By this action and as the accumulation is being built up thecarbon captures gaseous and condensed pollutants and likewise is subjectto physical and electrostatic influences whereby it is molecularlymodified to a form that lends itself to the production of activatedcarbon or carbon black. Since the sludge which is removed from thecollection container is rich in modified carbon, the sludge hassubstantial commercial value for a variety of industrial uses.

Preferably the collection means is such that there is reduction inpressure and in this zone of reduced pressure further ice contact isprovided. The reduction in pressure, which preferably is repeated withindicental lowering of the temperature of the reduced exhaust gas,provides conditions conducive to the ultimate removal of such smallquantities of pollutants as may be present in the exhaust gases removedfrom the primary ice contact chamber. The concommitant ice formation andsloughing off also occurs in the collection unit or zone of the systemand the resulting sludge supplements that carried into the collectionzone from the ice contact chamber.

In one embodiment the residual exhaust gases which are swept over thesludge in the collection chamber are caused to pass through a screenwhich provides further assurance that particulate, solid pollutants areremoved from the exhaust gases. However, in another embodiment thisobjective is obtained by the employment of zones of pressure reductionand baffles.

As a result of utilizing the foregoing in the practice of our inventiona very effective removal of noxious contaminants has been accomplished.The bulk of the residual exhaust gases merely consists of nitrogen,carbon dioxide and residual oxygen.

A further understanding of this invention and of the features andadvantages thereof will be apparent in connection with the followingdescription of preferred practice of this invention in connection withthe accompanying drawings wherein:

FIG. 1 is a flow diagram illustrating the utilization of one embodimentof our invention in the exhaust system of a motor vehicle comprisingconventional refrigerating means of a type employed for airconditioning;

FIG. 2 is a schematic showing of the evaporator section or zone whichcomprises the ice contact chamber and of the collection containercomprised in the collection zone and of the flow of materialtherethrough;

FIG. 3 is a side elevation, partly in section, of the ice contactchamber;

FIG. 4 is a side elevation of the refrigerant coil arrangement shown inFIG. 3, with part of the larger diameter coil removed for purposes ofclarity;

FIG. 5 is an end view of the refrigerant coils shown in FIG. 4;

FIG. 6 is a section on the line 6-6 of FIG. 3 with the refrigerant coilsremoved and showing the arrangement of baffles in the ice contactchamber;

FIG. 7 is a side elevation, partly in section, of the collectioncontainer;

FIG. 8 is an end view of the inlet end of the collection container;

FIG. 9 is a section taken on the line 9-9 of FIG. 7;

FIG. 10 is an end view of the exhaust end of the collection container;

FIG. 11 is a flow diagram which illustrates the utilization of anotherand preferred embodiment of our invention in the exhaust system of amotor vehicle;

FIG. 12 is a plan view, with certain parts broken away, of theevaporator zone or unit employed in the system shown in the flow diagramof FIG. 11;

FIG. 13 is an elevation of the right-hand end of the unit shown in FIG.12;

FIG. 14 is a plan sectional view of the evaporator unit taken on theline 14-14 of FIG. 13 with the outer casing removed;

FIG. 15 is a detail view, partly in section, taken on the line 15-15 ofFIG. 12;

FIG. 16 is a detail elevation, partly in section, taken on the line16-16 of FIG. 14 which shows the disposition of the baffles in the icecontact chamber;

FIG. 17 is a plan view of the collection unit or zone employed in thesystem shown in FIG. 11 taken on the line 17-17 of FIG. 18;

FIG. 18 is a sectional elevation of the collection unit taken on theline 18-18 of FIG. 17;

FIG. 19 is a sectional elevation taken on the line 19-19 of FIG. 17;

FIG. 20 is a sectional elevation taken on the line 20-20 of FIG. 17;

FIG. 21 is a sectional elevation taken on the line 21-21 of FIG. 17; and

FIG. 22 is a perspective detail of the portion of the collection unitwhich comprises successive constriction and expansion zones in thetravel of the exiting exhaust gases.

With reference to the flow diagram shown in FIG. I, a conventionalrefrigerating system or unit is indicated which comprises the compressor19, the condenser 11, the receiver 12, the expansion valve 13 and theevaporator 14. The cold, expanded refrigerant passes from the evaporatorto the suction valve 15 for return to the compressor 10. In thediagrammatic showing of FIG. 1 expansion valve 13 and the evaporator 14are part of the air conditioning equipment of a motor vehicle.

The relief valve and evaporator for such air conditioning equipment mayoptionally be employed in the practice of our invention. It is optionalequipment which may or may not be employed when utilizing our invention.

In the practice of our invention the compressed refrigerant, such asfreon, is directed from the receiver 12 by the line 16 to the expansionvalve 17 and the refrigerant under reduced pressure is directed by theline 18 to the evaporator coil 19 in the ice contact chamber 20. Thespent refrigerant may be returned to the suction valve by the line 21.However, in optional preferred practice of this invention the valve 22in the line 21 is closed and the valve 23 in line 24 is open fordirecting the residual and still cold refrigerant through therefrigerated coil 25 in the upper portion of the collection container 26from which the spent refrigerant is returned by the line 27 forreintroduction into the line 21 for return to the suction valve 15. Whenthe system is employed without using the coil 25, valve 22 is open andthe valve 23 is closed or the coil 25 and lines 24 and 27 may be omittedaltogether.

As further indicated in FIG. 1, the purifying means of this invention ispositioned downstream in the exhaust line 26 leading from the internalcombustion engine in the portion thereof subsequent to the muffler 29.To assist in the preliminary cooling of the exhaust gases prior to entryinto the purifying means of our invention the surface for heat transferto the surrounding atmosphere may be increased by conventional meanssuch as by the employment of a relatively large diameter exhaust lineand the employment of cooling tins of conventional design (not shown).The purifying action which is accomplished in the practice of ourinvention is indicated schematically in FIG. 2. In FIG. 2, thestructural details are not shown, especially in connection with thecoils. The structural details of the coils are shown in FIGS. 3 to 10.

In FIG. 3, the eshaust gases are shown entering the ice contact chamberfrom the exhaust pipe 28. Because of the greatly increasedcross-sectional flow capacity and the employment of baffles 30 and 31the kinetic energy of the moving exhaust gases is greatly reduced andthe exhaust gases are directed into intimate, direct contact with thesurfaces of the refrigerated coil 19. The refrigerant is introduced intothe coil from the line 18 and, as shown schematically in FIG. 2, itflows from the coil via the line 21. The effect of the expansion andevaporation of the refrigerant is such as to maintain the temperature ofthe surface of the coil 19 at a temperature so low as to not only causecondensation of moisture contained in the exhaust gases but also thebuildup of a body of ice 32 on the subsurface afforded by the surface ofthe coil 19. Upon continuing operation a condition of equilibrium isattained wherein the surface of the body of ice 32 is scrubbed by theincoming gases with continued condensation of water vapor and depositionof particular matter on the ice with formation of sludge which, as shownschematically in FIG. 2, sloughs off and falls to the bottom of the icecontact chamber carrying with it absorbed noxious gases, vapors, saltsand condensed liquids. The accumulated sludge in the bottom of the icecontact chamber is indicated at 33. The central portion of the baffles31 adjacent the bottom of the ice contact chamber is cut away, as shownin FIG. 6 and described more in detail hereinbelow, so as to permit thesludge under the influence of the kinetic energy of the rapidly movingexhaust gases to flow out of the ice contact chamber through the outletorifice 34. It is apparent that the exhaust gases are directed throughthe longitudinal extent of the ice contact chamber with a zigzag coursethat is imposed by the baffles 30 and 31 and that follows the course ofthe individual coils. In this ay an elongated zone of travel of theexhaust gases in direct turbulent contact with the ice on the coil isafforded where the above-described influences result in effectivedeposition of the pollutants and the concomitant sloughing off of asludge wherein the various pollutants are concentrated.

The outlet 34 of the ice contact chamber is shown schematically in FIG.2 as connected by a suitable line or hose 35 to the inlet 36 of thecollection container 26 wherein a body of sludge 37 gradually builds up,as indicated in FIG. 2, until enough has accumulated to warrant itsremoval.

When it is desired to clean out the sludge from the collection containerthis may be readily accomplished by removing the readily removableclosure 38 whereupon the sludge may be removed as by scraping it out orby the use of compressed air.

Within the collection container the exhaust gases are swept over thesurface of the sludge as it gradually accumulates in the collectioncontainer, as indicated by the arrows in FIG. 2. Before leaving thecollection container the residual exhaust gases pass through the screen39 which, as aforesaid, provides additional assurance for the capture ofany particulate matter. Moreover, and as aforesaid, the refrigerant coil25 in the upper portion of the collection container by its coolingeffect provides additional assurance of retention of pollutants absorbedin the sludge and on the surfaces of particles captured by the screen39. The residual exhaust gases which now have been purified are passedinto the atmosphere through the outlet 40.

The details as regards the construction of the ice con tact chamber areshown in FIGS. 3, 4, 5 and 6. The ice contact chamber 20 in the specificembodiment shown is cylindrical. The exhaust line 28 is connected to theforward end 41 with the interposition of the flared portion 42 whichassists in decelerating the exhaust gases and distributing themthroughout the cross-section of the chamber. The chamber itself, forconvenience in assembling, is made in two halves, namely, the upper half20A and the lower half 208, that are secured in complementary opposedrelation by the strips 43 which are secured to and are upstanding fromthe lower half 20B and to which the lower margins of the upper half 20Amay be secured as by set screws 44. Depending from the inner surface ofthe upper half 20A and secured thereto are the aforesaid baffles 30which are shaped and positioned, as shown most clearly in FIG. 3, so asto conform to the configuration between the spaces between theindividual coils of the larger coil 19A of the concentric coils 19A and1913 which make up the coil 19.

In similar fashion, the baffles 31 are secured to the inner surface ofthe lower half 20B of the ice contact chamber except that each of thebaffles 31 has the cutout portion 45 in the region thereof immediatelyabove the bottom of the ice contact chamber. The baffles 30 and 31 serveto direct the exhaust gases in immediate direct contact with the ice onthe surface of the coils 19A and 198. Any sludge which sloughs off fromthe body of ice on the surface of the coils 19A and 19B falls to thebottom of the chamber 20 and with the assistance of the rapidly movingexhaust gases is urged along the bottom of the chamber 20 through theopenings afforded by the cut-out portions 45 of baffles 31 for exitalong with the residual combination gases through the exit opening 34.

As shown in particular in connection with FIGS. 4 and 5, the refrigerantwhich is introduced into the coil 19 through the line 18 first travelsthrough the larger evaporator coil 19A from adjacent the outlet end ofthe ice contact chamber to adjacent the inlet end. The refrigerant thentravels through the centrally disposed line 46 to the end of the smallerevaporator coil 19B and travels therethrough for exit into the returnline 21 adjacent the end of the ice contact chamber here the exhaustgases are introduced.

The detail of the collection container is shown in FIGS. 7 8, 9 and 10.The residual exhaust gases emanating from the outlet 34 of the icecontact element chamber travel through the connecting line or hose 35 tothe inlet 47 of the collection container 26. The collection container ishorizontally disposed and is of sufficient diameter and length to permita substantial quantity of sludge 37 to accumulate therein. The outlet 40of the collection container is at the opposite end thereof so that theincoming gases sweep over the accumulating sludge, as indicated by thearrows. It is prefer able according to this invention that thecollection container be provided with the screen 39 through which theexhaust gases pass in flowing toward the outlet 40.

While it is not essential to the practice of this invention, it ispreferable that an out-of-contact thermal exchanger be disposed in theupper portion of the collection container so as to maintain the residualexhaust gases in a cool condition favorable to the retention of noxiouspollutants in the sludge that is collected in the collection container.In the embodiment shown in the drawings the thermal exchanger may beginthe form of the U-shaped tubing 25 connected by the lines 24 and 27 tothe refrigerant return line 21 whereby, upon closing the valve 22 andopening the valve 23, refrigerant that is discharged from the coil 19 ofthe ice contact chamber may be caused to flow through the tubing 25before return to the suction side of the compressor.

The amount of water vapor in waste combustion gases may vary and in theevent of the occurrence of sufficient free water in the ice contactchamber and in the collection container it is in accordance withpreferred practice of this invention to return free water by a returnline to the exhaust line at a point prior to the ice contact chamber andpreferably to a point on the exhaust line ahead of the muffler. Theprovision of such a return line is shown diagrammatically in FIG. 1 bythe line 48 which has its inlet adjacent the forward end of thecollection container 26 and which contains a small pump 49 ofconventional design, which may be operated from the battery of the motorvehicle, whereby the water is pumped so as to be returned by line 50into the exhaust line, preferably in the form of a spray, when the valve51 is open and the valve 52 in line 53 is closed. This has the advantageof assisting in the cooling of the exhaust gas whereby ice formation inthe ice contact chamber may be accomplished more efficiently. Moreover,the additional water which is recirculated through the ice contactchamber adds to the efficiency with which pollutants are taken up on theice surface and sloughed away into the collection container. If thewater collection becomes excessive the excess water may be removed byopening valve 52 in line 53. Line 53 may be directed to waste or,alternatively, may be directed into the cooling system of the vehicle.It is preferable to withdraw the water through a filter 54, especiallywhen excess water is directed to waste through line 53.

Moreover, the production and recovery of carbon as herein described,wherein unburned carbon particles are collected which may have residualhydrocarbons associated therewith and lwhereby the particles as they arecollected are contacted with the residual combustion bases which containoxygen and carbon dioxide and other substances having an influence onthe activity of the carbon surface, especially when the carbon particlesare moist, has other and more general applica tion.

A further embodiment of this invention is shown in FIGS. 11-22. Theevaporator and collection units or zones, which units successivelyscavenge pollutants from the exhaust gases and collect the scavengedpollutants so that they are not discharged into the atmosphere, areshown comprised in the flow diagram of FIG. 11. In this flow diagram theevaporator unit and the collection unit are disposed in successiondownstream of the exhaust line 60 which has the muffler 61 therein. Therefrigeration system is conventional in that it comprises the compressor62, the condenser 63, the receiver 64 from which compressed refrigerantsuch as freon is taken by the line 65 to the expansion valve 66. Thecold refrigerant is taken from the expansion valve 66 by the line 67into the evaporator unit which is indicated generally by the referencecharacter 68. The refrigerant successively passes through the evaporatorunit and the collection unit, as will be described in detail inconnection with FIGS. 12-22. The refrigerant after emerging from thecollection unit is returned to the suction valve 69 by the line 70 andpasses from the suction valve 69 to the compressor by the line 71.

The evaporator unit 68 comprises a preferred embodiment of the icecontact chamber. ln this embodiment the refrigerant line 67 is disposedin a coil of the zigzag type wherein the several straight portions aresurrounded in proximate spaced relation with respect thereto byelongated conduit means which may conveniently consist of lengths ofpipe roughly corresponding in diameter with the diameter of the exhaustpipe.

More specifically, the portion of the exhaust line 72 which isdownstream of the muffler enters the casing 73 of the evaporator unit 68and extends from the righthand extremity of the unit substantially tothe left-hand extremity. Just prior to the entry of the exhaust line 72into the casing 73 the refrigerant line 67 enters the exhaust line andextends from right to left concentrically with the exhaust line 72. Itis maintained in this position by the supporting baffles 74.

The left-hand extremity of the exhaust line 72 terminates in a header 75which directs the exhaust gases so as to enter and pass through thetubing 76 proceeding from left to right in the annular space surroundingthe continuation of the refrigerant line 67. The header 75 may be unitedwith the exhaust line 72 and the tubing 76 in any suitable manner suchas by welding. Similarly, the Ushaped portion 77 of the refrigerant line77 may be secured in place with respect to the straight reaches of therefrigerant line 67 by welding. This manner of assembly may also beemployed in connection with the other corresponding parts of the unit.The tubing 76 discharges into the header 78 which serves to direct theexhaust gases into and through the adjoining tubing 79 within which afurther reach of the refrigerant line 67 is concentrically disposed.Another header 80 directs the exhaust gases into and through the tubing81 wherein another reach of the refrigerant line 67 is concentr'icallydisposed and the header 83 directs the exhaust gases into the tubing 83for passage therethrough in relation to the continuation of therefrigerant line 67 that is concentrically disposed therein. Thedisposition of the exhaust line 72 in relation to the refrigerant line67 and the header 75 is shown in FIG. 15. FIG. 16 shows the dispositionof the baffles 74 in the exhaust line 72 and the way by which therefrigerant line 67 is held in concentric relation with respect to theexhaust line 72, it being understood that there is a plurality ofbaffles 74 alternately disposed on opposite sides of the refrigerantline 67. As exemplified above, the term coil as used herein is notlimited to a helical coil but has application to zigzag and otherconfigurations by which a substantial longitudinal extent of travel maybe afforded in a limited space.

The casing 73 comprises the oval portion 84 which may be made of sheetmetal, plastic or other appropriate material and which is secured to theend panels 85 and 86 through which the exhaust line and the dischargetubing 83 pass at opposite ends thereof. The casing 73 serves to protectthe ice contact chamber from possible damage due to flying stones or thelike. It also shields the ice contact chamber from heat from the road.The casing 73 preferably is of oval shape in general conformity to theconventional oval shape of the mufflers commonly used in automobiles.However, the casing could be any other convenient shape, such asrectangular, square or circular.

The scavenging action which takes place in the evaporator unit issimilar to that which has been described hereinabove in connection withthe embodiment of this J. invention shown in FIGS. 11(). However, theconstruction of the ice contact chamber as illustrated in FIGS. 12-15 ispreferred in that the construction is such as to take more efiicientadvantage of thermal precipitation in causing the pollutants in theexhaust gases to become deposited on the body of ice within the icecontact chamber. The refrigerant that enters the evaporation unit is ata temperature sufficiently low as to cause not only condensation ofwater vapor contained in the exhaust gases but also the freezing of thecondensed water vapor on the surface of the refrigerant line 67 with thebuild-up thereon of a body of ice which presents an extended surfacearea that is in contact with the exhaust gases in their zone of travelthrough the exhaust line 72, the tubings 76, 79, 81 and 83 and theheaders 75, 78, 80 and 82. The body of ice adhering to the exhaust line67 is shown in FIG. 12 by the reference character 87. For the sake ofclarity, the body of ice 87 has been shown only in FIG. 12 and only in asingle location in said figure. However, it is to be understood that thebody of ice which builds up extends throughout the entire length of therefrigerant line 67 that is within the casing 73.

Our invention takes advantage of the enhanced scavenging action affordedby thermal precipitation. In a thermally and electrically uniform gasthe molecular bombardment of particular material is uniform in alldirections. By providing a cold refrigerated surface in proximate spacedrelation to a warmer zone such as that provided adjacent the warmersurface presented to the exhaust gases by the inner surface of theexhaust line 72, it follows that in the tubing sections 76, 79 and 83and the headers 75, 78, 80 and 82 the temperature gradient is such as totend to cause deposition on the colder surface. Thus the moisture closeto the refrigerdroplets which in turn become deposited on the chilledsurface and freeze. Gaseous pollutants contained in the exhaust gasesbecome absorbed in the chilled condensate and this is promoted by reasonof the fact that such absorption or solution is increased as thetemperature decreases. The chilled condensate containing absorbedgaseous pollutants then, because of the thermal precipitationconditions, tend to move to the refrigerated surface where they becomeentrapped by the ice. As the exhaust gases move through the annularspace between the refrigerant line and the exhaust line or other tubingthe influences to which the exhaust gases are subjected, including theinfluences afforded by the baffles 74, are such that the electrostaticcharges which become imposed on the gaseous and particulate materialsare subject to repeated reversals with the result that oppositelycharged units of matter inevitably become adjacent and attracted to eachother so as to become condensed and deposited on the surface of the ice.The resultant electrostatic precipitation effect is more comprehensivethan an electrostatic precipitator since an electrostatic precipitatordepends on a single fixed charge and the precipitation of thosecomponents only that are precipitated responsive to said charge.

The build-up of ice on the refrigerant line results in some decrease inthe cross-section of the ammulus which surrounds the refrigerant linewith resultant increase in velocity and decrease in the pressure of thegases. This aids in the scrubbing action without creating back pressureon the engine because the volume of the gas contracts upon coolingduring its travel along the ice surface. The ionization of the gases andthe creation of turbulence to assist in the scrubbing or scavengingaction afforded by the extended area of the ice surface over which thegases flow are promoted by the successive baffles 74.

As has been described in connection with the embodiment shown in FIGS.l-lt), an equilibrium condition eventually is reached at which themovement of the exhaust gases across the ice coating of the refrigerantline erodes the ice crystals with resultant sludging off of a moistsludge which contains the pollutants scavenged from the exhaust gases.This sludge is moved along by the kinetic energy of the moving exhaustgases and this movement is not interfered with by the baffles 74 sincethe baffles are constructed and positioned so as to leave a zigzagchannel along the bottom of the exhaust line 72 and along the bottom ofthe tubing sections 76, 79, 81 and 83 through which the sludge is movedfor eventual discharge from the evaporator unit through the tubing 83.The eroded ice which as either fine or aggregate particles is propelledby the exhaust gases further scavenges the particulate matter from theexhaust gases.

Referring now to FIGS. 17-22, the exhaust gases and the sludge whichemerge from the tubing 83 of the evaporator unit 68 are transferred toand enter in the tube section 88 atthe entrance of the collection unit,which is indicated generally by the reference character 89. The tubing83 is shown as maintained in communication with the tube section 88 by asmall length of flexible tubing or hose 90 which is clamped in place byclamps 91. The refrigerant line 67 is continued concentrically and forconvenience in assembly the portion of the refrigerant line 67 withinthe collection unit may be detachably joined to the portion of therefrigerant line 67 in the evaporator unit by means of a coupling 92. Ahose coupling 122, which may be similar to hose coupling 90, preferablyis positioned in exhaust line 72 between the muffler and the evaporator.

The tube section 88 discharges into the interior of a collection unitand the initial travel is from right to left in the space between theside wall 93 and the partition 94. Except for the extreme right-hand endof the collection unit, there is a reservoir 95, the roof 96 of which isspaced substantially above the bottom 97 of the collection unit. In theregion between the top 98 of the collection unit and the roof 96 of thereservoir, baffles 99 are disposed in conformity with the serpentineconfiguration of the refrigerant line 67 in that portion thereof whichextends from right to left of the collection unit immediately after thetube section 88 enters the collection unit. The roof of the reservoir inthis portion as well as in other portions of the collection unit isprovided with a multiplicity of holes 102 and as the exhaust gases enterthe above-described portion of the collection unit sludge which is beingswept along by the combustion gases as the sludge that enters thecollection unit tends to become deposited due to the greatly enlargedflow capacity of this portion of the collection unit as compared withentrance tube 88. Some of the sludge remains on the upper surface of theroof 96 of the reservoir and some of the sludge, including ice crystals,also passes through the holes 102 into the reservoir 95 together withmost of the water.

The coil or serpentine of the refrigerant line in this portion of thecollection unit performs the function hereinabove described, namely,that of a scavenger. However, in this portion of the over-all systemmost of the pollutants already have been removed and the function of theice carried by the refrigerant line is that of removing small amounts ofpollutants that had not previously been removed from the combustiongases while at the same time permitting the combustion gases to continuetheir travel in a greatly purified condition.

In order to further act upon any residual pollutants the exhaust gasesare directed through a channel defined by the roof 96 of the reservoir95, the roof 98 of the collection box, the partition 94 and thepartition 100. Within the channel as thus defined there are opposingwall members 101 which provide a succession of gradual contractions andsudden expansions of the gases in moving from left to right. Thecombination of gradual contractions followed by sudden expansions causesthe traveling gases to lose further heat. This action also tends toconcentrate any melt water still entrained in the gases. Any water andsludge which tends to be collected and removed from the travelingexhaust gases is free to pass into the reservoir 95 through the holes102. in order to better assure the drainage of water and sludge throughthe holes into the reservoir in this portion of the unit wires 103 aredisposed in a position that is transverse to the flow of the gas. Theweirs also serve to further contract the opening so as to obtain theabove-described effect of knocking out pollutants from the stream ofcombustion gases by accelerating the gases for passage through arestriction and then permitting the gases to expand with resultantcooling effect. The refrigerant line 67 extends from left to right ofthis portion of the collection unit and any residual moisture tends tocondense and freeze thereon so as to provide an ice surface in thisportion of the unit and so as to maintain the presence of the icesurface and its scavenging effect on any residual pollutants in theexhaust gases that flow therealong.

The exhaust line 104 extends from adjacent the righthand end of thecollection unit through the left-hand end for discharge into theatmosphere. The refrigerant line is extended therethrough concentricallytherewith and contains baffles 105 which are similar to the baffles 74.While at this stage virtually all of the pollutants have been removedfrom the combustion gases prior to entry of the combustion gases intothe exhaust line 104, nevertheless if there is any residual amount ofpollutant material in the combustion gases the residual pollutants tendto be collected on the body of ice on the surface of the refrigerantline due to the thermal precipitation effect hereinabove described incombination with the turbulence induced by the baffles 105. Any slightamount of residual aqueous sludge is permitted to drain from the regionadjacent the left-hand end of the exhaust line 104 through the holes106.

The refrigerant having served its purpose leaves the exhaust line 104through the low pressure return line hereinabove described. The materialwhich drains into the reservoir in the portion thereof between the sidewall 93 and the partition 94 is free to migrate to the drain line 107through the arches 108 in the bottom of the partition 94. The otherportions of the reservoir 95 also tend to drain toward the drain line107 but most of the solid material is left in the collection unit eitheron the roof of the reservoir or in the reservoir itself.

The drain that drains from the collection unit through the drain line107 consists largely of water which is permitted to drain into the waterreservoir 109 from which it flows through the strainer 112 to thecentrifugal pump 113 which forces it through the line 114 to the spraynozzle 115 where it is sprayed into the exhaust gases in the exhaustline 60 prior to their entry into the muffler 61. The end of thereservoir 109 is closed by door 110 hinged at hinge which normally isheld in fluid-tight relation by spring 117 so that in the event offreezing the door can open to relieve pressure. The strainer preferablyis readily detachable as by the provision of removable hose couplings118 and 119 similar to hose coupling 90. Wye fittings 120 and 121 areincluded in the lines 114 and 111, respectively, so as to permitdrainage of water from the water recirculation system when the pump 113is not in operation and thereby eliminate the possibility of freezing incold weather when the engine is not in operation. The wye fittingsfunction responsive to the velocity of the pumped water to preventdrainage when the pump is in operation while permitting drainage when itis not. The lines adjacent thereto may be slightly inclined so as todrain toward these fittings.

Thewater which is sprayed into the exhaust gases becomes vaporized andthe vaporization of the water tends to cool the exhaust gases. Byspraying the water into the exhaust gases it also is the case thatsufficient water vapor is maintained in the entering exhaust gases so asto insure the continued presence of a body of ice which coats therefrigerant line throughout the various portions of the system. Sincesome water vapor is continously being supplied by the burning of thefuel in the internal combustion engine, the quantity of water tends tobuild up and if there should be any excess it will drain out of the tailpipe 104. If water is desired in starting up, water may be introducedinto the reservoir 109 through the inlet 116 which is provided with ashut-off valve (not shown) that is closed during normal operation. Thepump is adjusted so as to provide the normal amount of recirculatedwater for maintaining the ice in the system during ordinary conditionsof operation. The water recirculating system is not essential since thewater vapor content of the exhaust gases is around 30 percent and isample to build up and maintain a body of ice on the refrigerant line.

Eventually, the amount of collected sludge will have become accumulateduntil it becomes desirable to clean it out. This may be convenientlyaccomplished by blowing it out with compressed air. Thus after havingmoved the couplings 90 and 118 out of the way compressed air may besupplied at the tail pipe. Compressed air also may be introduced throughthe inlet 116. If desired, the bottom 97 of the collection box could beremovable. The water reservoir 109 also may be cleaned up swinging openthe hinged door 110.

In the operation of an automobile, for example, the engine proper firesat about 1,370 to 1,480F. while the exhaust at the entrance of theexhaust pipe usually runs from about 350 to 480F. As the exhuast gasflows in contact with the relatively large area of surface of theexhaust pipe it becomes cooled rapidly and in ordinary operation themuffler of an automobile operates at a temperature of only about 125 to250F. The tail pipe extending from the muffler becomes quite cool andits temperature will range from about 80F. to 150F.

Since the evaporator unit that is employed in the practice of thisinvention which contains the ice contact chamber is disposed downstreamfrom the muffler, the exhaust gases by the time they reach theevaporator unit will run at a temperature of about lF. If furthercooling is desired, the exhaust pipe and/or the muffler may be suppliedwith air cooling fins of conventional type.

The inherent economy which may be had in the practice of this inventionmay be illustrated in connection with typical operation of an automobileso that the gasoline comsumption is at the rate of about 18 lbs. perhour. The moisture content of the exhaust gases usually is of the orderof 30 percent. In other words, there is about 5.4 lbs. of water producedper hour, or 0.0015 lb. of water per second. Assuming 100F. as typicalof the temperature at which the exhaust gases enter the evaporator unitand assuming that the water content is converted to ice at F. and thatthe residual gas likewise is cooled to 10F, the BTUs which have to bewithdrawn are approximately 3,345 BTU per second. Since in accordancewith accepted engineering practice the removal of 12,000 BTUs per hourequals 1 ton of refrigeration, the refrigeration load under theoperating conditions above-described is approximately 0.20 ton per hour.To supply this refrigeration, that which is required according toaccepted conversion principles in a compressor of the order ofone-quarter to onethird horsepower. This is approximately the horsepowerof the compressors that are extensively used for providing therefrigeration in conventional air conditioning equipment in anautomobile. It is apparent, therefore, that the refrigeration requiredis only a very small fraction of the horsepower of engines commonlyemployed in automobiles and trucks and that the expense incident to thevery effective removal of pollutants from the exhaust gases isapproximately comparable to that which is incident to the operation ofthe air conditioning equipment of an automobile.

While this invention has been illustrated in connection with embodimentsthereof that are located downstream with respect to a muffler, it alsois the case that units embodying this invention may be employed in anexhaust line wherein the muffler is omitted since the travel of thegases within the units is such as in large measure or even entirely toserve the function of a muffler. However, in such case it is preferableto assist in the dissipation of heat from the exhaust pipe by theemployment of air cooling fins or the employment of a large diameterexhaust pipe so as to compensate for the omission of the muffler.

While the evaporator coil 19 of the embodiment of this invention shownin FIGS. 1 to 10 and the refrigerant line 69 of the embodiment shown inFIGS. 1 1 to 22 become rapidly cooled to ice forming temperature uponstarting the internal combustion engine with which these embodiments arerespectively utilized it may be desirable in order to minimize theescape of pollutants during the starting up period to introduce a liquidgaseous material, of a type having a sufficiently low temperature whenit is permitted to expand rapidly, into the ice contact chamber withrapid reduction in pressure and temperature and concommitant rapidchilling of the subsurface for the ice that is provided as exemplifiedby the coil 19 or the refrigerant line 67. For example, as shown in FIG.11 the apparatus may comprise a reservoir 123 for such a liquifiedgaseous material from which such a liquified gaseous material may bedirected into the ice contact chamber 68 by the line 124 which iscontrolled by the valve 125. The valve 125 may be manually controlled toinject such a liquified gaseous material at the same time that theinternal combustion engine is started and preferably is of a known typewhich automatically shuts off after an injection period of only a fewmoments. Alternatively the valve 125 may be automatically actuated toinject such a liquified gaseous material when the starter button or keyfor the internal combustion engine is actuated to start the engine,through control lines 126.

It is to be understood that the apparatus embodying and utilized in thepractice of this invention may take forms other than those that havebeen described merely for purposes of illustration. Moreover, whileseparate interconnected units have been shown, it is apparent that theassembly may be integrated in a common external casing which, ifdesired, also could take in a muffler either of conventional type orespecially adapted for use with equipment embodying our invention.

We claim:

1. The method of removing pollutants from waste combustion gases whichcomprises directing the combustion gases into direct contact with asurface of .ice which is supported by a heat exchange subsurface andwhich presents an extended area of ice surface for contact with saidcombustion gases, flowing said gases while confined by chamber meansthrough an extended zone of travel in turbulant contact with saidsurface of said ice, maintaining said subsurface at a temperaturesufficiently low at which moisture contained in said combustion gasesbecomes condensed and frozen on said subsurface and builds up thereon abody of ice the surface of which is in direct contact with said gasesduring their travel through said zone and on which particulatepollutants become deposited and gaseous pollutants become taken up andcontinuing to direct combustion gases into contact with the surface ofsaid body of ice travelled by said gases with concomitant sloughing offfrom the ice surface of an aqueous sludge containing pollutantsscavenged from said gases by becoming deposited and taken up on saidsurface, moving said sludge as it is formed and combustion gases into acollection zone, collecting the sludge in a container in said zone, anddirecting residual combustion gases separated from said sludge out ofsaid zone.

2. A method according to claim 1 wherein movement of said sludge intosaid collection zone is assisted by the kinetic energy of residual gasesin direct contact therewith.

3. A method according to claim 1 wherein the pressure of said exhaustgases is substantially reduced during travel through said travel zone.

4. A method according to claim 1 wherein the waste combustion gases arethe exhaust gases of an internal combustion engine.

5. A method according to claim 1 wherein one of said pollutants in thewaste combustion gases that is deposited on and sloughed off from saidice surface is in the form of unburned carbonaceous particles andwherein the surfaces of said carbonaceous particles are modified by theaction of the waste combustion gases that are swept over the sludge inthe collection zone.

6. A method according to claim 1 wherein said body of ice is formed on asubsurface presented by a refrigerant line disposed in proximate spacedrelation with respect to the inner surface of elongated conduit meansand the combustion gases are passed through said conduit means in directcontact with the surface of the body of ice formed on the surface ofsaid refrigerant line.

7. A method according to claim 1 wherein a liquified gaseous materialhaving a sufficiently low temperature is introduced into said chambermeans causing rapid reduction in pressure and temperature within thechamber means and concomitant rapid chilling of said subsurface to thefreezing temperature of the moisture contained in said combustion gases.

8. A method according to claim 1 wherein the residual combustion gasesare directed through the collection zone so as to pass over saidcollection container and wherein the so directed residual gases arefurther chilled by contact with a chilled surface disposed above saidcollection container.

9. A method according to claim 8 wherein said chilled surface is in theform of ice formed on a subsurface and the subsurface is maintainedsufficiently cold to maintain ice thereon.

10. A method according to claim 9 wherein the exhaust gases directedthrough the collection zone while passing over the collection containerin contact with ice on said subsurface are subjected to a succession ofpressure drops which assist in completing the scavenging of pollutantsfrom the exhaust gases.

1]. A method according to claim 1 wherein prior to contact of thecombustion gas with the ice surface water is sprayed into the combustiongas with resultant increase in the water vapor content of said gasesthat condenses and freezes in the formation of the body of icepresenting said surface.

12. A method according to claim 11 wherein said combustion gases passthrough a muffler prior to contact with the ice surface and whereinwater is sprayed into the exhaust gases upstream in relation to themuffler.

13. A method according to claim 11 wherein water is separated from thecollected sludge and said water so separated is sprayed into saidcombustion gases prior to contact with the ice surface.

14. Apparatus for purifying waste combustion gases which comprises anice contact chamber having an inlet and an outlet spaced from saidinlet, elongated conduit means within said chamber, means for directingwaste combustion gases through said inlet into said chamber, saidchamber defining confining means for confining said gases for extendedtravel of said gases in intimate contact with the external surface ofsaid conduit means during travel through said chamber from said inlet tosaid outlet, baffle means within said chamber to induce turbulence ofsaid gases during travel through said chamber in intimate contact withsaid external surface of said conduit means, a refrigerating unit fordirecting a refrigerant through said elongated conduit means at atemperature sufficiently low to condense moisture in said combustiongases and convert at least a substantial proportion thereof to iceformed on the external surface of said conduit means in direct contactwith said gases, continuous channel means comprised in said chamberextending from adjacent said inlet to said outlet, said channel meansbeing disposed underneath said elongated conduit means for the receptiontherein of liquid and particulate accumulations released from thesurface of said elongated conduit means and for travel therealong in thedirection of travel of said gases toward and into said outlet, acollection container for said accumulations having an inlet and anoutlet, conduit means connected between said chamber and said containerwhich directs waste gases and said accumulations emerging from saidoutlet of said ice contact chamber into said collection container, saidcollection container including separating means for the retention ofsaid accumulations therein while permitting the travel of waste gasestherethrough from said inlet to said outlet of said collection containerfor discharge therefrom.

15. Apparatus according to claim 14 wherein said collection containercomprises a pressure reducing portion the cross sectional flow capacityof which for waste gases flowing therethrough in relation to that ofsaid inlet of said collection container is such as to result in areduction in pressure of gases after said gases enter said collectioncontiner through said inlet thereof and which comprises in the region ofsaid portion of said collection container through which gases flow anice supporting member presenting an extended external surface disposedfor contact with said gases prior to emission of said gases from theoutlet of said collection container and refrigerating means formaintaining said surface of said member at a temperature sufficientlylow to condense thereon water vapor contained in said gases and convertsame to ice.

[6. Apparatus according to claim 15 wherein said collection containerdownstream with respect to said pressure reducing portion comprises atleast one contraction in the cross sectional flow capacity for saidwaste gases followed by a further pressure reducing portion wherein thewaste gases come in contact with the external surface of said icesupporting member.

17. Apparatus according to claim 14 wherein said means for directingwaste combustion gases through said inlet into said chamber comprisesspray means for spraying water into said waste combustion gases prior toentry of said gases into said ice contact chamber.

18. Apparatus according to claim 17 wherein said means for directingwaste combustion gases through said inlet into said chamber includes amuffler through which said gases pass prior to passage through saidinlet and wherein said spray means for spraying water into said gases islocated so as to spray water into said gases prior to their passagethrough said muffler.

19. Apparatus according to claim 17 which comprises drain means fordraining from said collection container free water collected in saidcontainer, water recycling means comprising a return line for directingwater from said drain means through said return line to said spraymeans, and a pump for pumping water removed from said collectioncontainer by said drain means to said spray means.

20. Apparatus for purifying waste combustion gases which compriseselongated conduit means, a refrigerating unit for directing arefrigerant through said conduit means at a temperature sufficiently lowto form ice on the surface thereof by the condensation and freezingthereon of moisture contained in gases in contact therewith, an icecontact chamber in the form of an elongated passage having an inlet andan outlet spaced from said inlet the inner surface of which is inproximate spaced relation with respect to the external surface of saidelongated conduit means for extended travel of gases therethrough incontact with the external surface of said elongated conduit means, meansfor directing waste combustion gases into the inlet of said elongatedpassage for passage therethrough to said outlet, a succession of baffleswithin said passage which impart turbulence to said gases during theirtravel therethrough in contact with the external surface of saidelongated conduit means, channel means comprises in said passage anddisposed underneath said elongated conduit means for the receptionofliquid and particulate accumulations released from the surface of saidelongated conduit means, said channel means being adapted for the travelof said liquid and particulate accumulations received therein in thedirection of travel of gases passing through said passage for dischargewith said gases from the outlet of said passage, a collection containerfor said accumulations having an inlet and an outlet, conduit meansconnected betweeen said chamber and said container which is disposed todirect waste gases and said accumulations emerging from said outlet ofsaid passage into said collection container through said inlet thereof,said collection container including separating means for the retentionof said accumulations therein while permitting travel of waste gasestherethrough from said inlet to said outlet of said collection containerfor discharge therefrom.

21. Apparatus according to claim 20 wherein said elongated conduit meansand said passage comprised in said ice contact chamber are respectivelyin coil form having a plurality of reaches disposed approximatelyhorizontally.

22. Apparatus according to claim 21 wherein said elongated conduit meansis disposed substantially concentrically within said passage and whereinsaid baffles extend partially across said passage with the inner marginsubstantially vertically disposed and cut away to accommodate a portionof the external surface of said elongated conduit means, said bafflesbeing disposed on opposite sides of said elongatee conduit means instaggered relation to provide support for said conduit means and leavingsubstantially unobstructed said channel means so as to permit travel ofsaid liquid and particulate accumulations along said channel means tosaid outlet of the said passage comprises in said ice contact chamber.

23. Apparatus according to claim 20 wherein said collection containercomprises an elongated passage for the travel of gases from said inletto said outlet of said collection container, a receptacle for liquid andparticulate accumulations disposed underneath said elongated passage, anelongated conduit means the external surface of which is in proximatespaced relation with respect to the inner surface of said passage insaid collection container, and refrigerating means for directing arefrigerant through said elongated conduit means at a temperaturesufficiently low to condense water vapor on said external surfacethereof and convert it to ice.

24. Apparatus according to claim 23 wherein said elongated conduit meansin said passage in said collection container is an extension of theelongated conduit means within the passage comprised in said ice contactchamber.

25. Apparatus according to claim 24, which also comprises a containerfor a liquified gaseous material having a sufficiently low temperatureand valve controlled means for injecting said liquified gaseous materialfrom said container into said ice contact chamber, whereby on startingthere is a rapid chilling of the ice contact chamber so as to produceice therein substantially immediately.

26. Apparatus according to claim 25 which comprises an engine startingswitch and means for actuating said valve controlled means responsive toactuation of said engine starting switch.

2. A method according to claim 1 wherein movement of said sludge intosaid collection zone is assisted by the kinetic energy of residual gasesin direct contact therewith.
 3. A method according to claim 1 whereinthe pressure of said exhaust gases is substantially reduced duringtravel through said travel zone.
 4. A method according to claim 1wherein the waste combustion gases are the exhaust gases of an internalcombustion engine.
 5. A method according to claim 1 wherein one of saidpollutants in the waste combustion gases that is deposited on andsloughed off from said ice surface is in the form of unburnedcarbonaceous particles and wherein the surfaces of said carbonaceousparticles are modified by the action of the waste combustion gases thatare swept over the sludge in the collection zone.
 6. A method accordingto claim 1 wherein said body of ice is formed on a subsurface presentedby a refrigerant line disposed in proximate spaced relation with respectto the inner surface of elongated conduit means and the combustion gasesare passed through said conduit means in direct contact with the surfaceof the body of ice formed on the surface of said refrigerant line.
 7. Amethod according to claim 1 wherein a liquified gaseous material havinga sufficiently low temperature is introduced into said chamber meanscausing rapid reduction in pressure and temperature within the chambermeans and concomitant rapid chilling of said subsurface to the freeziNgtemperature of the moisture contained in said combustion gases.
 8. Amethod according to claim 1 wherein the residual combustion gases aredirected through the collection zone so as to pass over said collectioncontainer and wherein the so directed residual gases are further chilledby contact with a chilled surface disposed above said collectioncontainer.
 9. A method according to claim 8 wherein said chilled surfaceis in the form of ice formed on a subsurface and the subsurface ismaintained sufficiently cold to maintain ice thereon.
 10. A methodaccording to claim 9 wherein the exhaust gases directed through thecollection zone while passing over the collection container in contactwith ice on said subsurface are subjected to a succession of pressuredrops which assist in completing the scavenging of pollutants from theexhaust gases.
 11. A method according to claim 1 wherein prior tocontact of the combustion gas with the ice surface water is sprayed intothe combustion gas with resultant increase in the water vapor content ofsaid gases that condenses and freezes in the formation of the body ofice presenting said surface.
 12. A method according to claim 11 whereinsaid combustion gases pass through a muffler prior to contact with theice surface and wherein water is sprayed into the exhaust gases upstreamin relation to the muffler.
 13. A method according to claim 11 whereinwater is separated from the collected sludge and said water so separatedis sprayed into said combustion gases prior to contact with the icesurface.
 14. Apparatus for purifying waste combustion gases whichcomprises an ice contact chamber having an inlet and an outlet spacedfrom said inlet, elongated conduit means within said chamber, means fordirecting waste combustion gases through said inlet into said chamber,said chamber defining confining means for confining said gases forextended travel of said gases in intimate contact with the externalsurface of said conduit means during travel through said chamber fromsaid inlet to said outlet, baffle means within said chamber to induceturbulence of said gases during travel through said chamber in intimatecontact with said external surface of said conduit means, arefrigerating unit for directing a refrigerant through said elongatedconduit means at a temperature sufficiently low to condense moisture insaid combustion gases and convert at least a substantial proportionthereof to ice formed on the external surface of said conduit means indirect contact with said gases, continuous channel means comprised insaid chamber extending from adjacent said inlet to said outlet, saidchannel means being disposed underneath said elongated conduit means forthe reception therein of liquid and particulate accumulations releasedfrom the surface of said elongated conduit means and for traveltherealong in the direction of travel of said gases toward and into saidoutlet, a collection container for said accumulations having an inletand an outlet, conduit means connected between said chamber and saidcontainer which directs waste gases and said accumulations emerging fromsaid outlet of said ice contact chamber into said collection container,said collection container including separating means for the retentionof said accumulations therein while permitting the travel of waste gasestherethrough from said inlet to said outlet of said collection containerfor discharge therefrom.
 15. Apparatus according to claim 14 whereinsaid collection container comprises a pressure reducing portion thecross sectional flow capacity of which for waste gases flowingtherethrough in relation to that of said inlet of said collectioncontainer is such as to result in a reduction in pressure of gases aftersaid gases enter said collection continer through said inlet thereof andwhich comprises in the region of said portion of said collectioncontainer through which gases flow an ice supporting member presentingan extended external surface disposed foR contact with said gases priorto emission of said gases from the outlet of said collection containerand refrigerating means for maintaining said surface of said member at atemperature sufficiently low to condense thereon water vapor containedin said gases and convert same to ice.
 16. Apparatus according to claim15 wherein said collection container downstream with respect to saidpressure reducing portion comprises at least one contraction in thecross sectional flow capacity for said waste gases followed by a furtherpressure reducing portion wherein the waste gases come in contact withthe external surface of said ice supporting member.
 17. Apparatusaccording to claim 14 wherein said means for directing waste combustiongases through said inlet into said chamber comprises spray means forspraying water into said waste combustion gases prior to entry of saidgases into said ice contact chamber.
 18. Apparatus according to claim 17wherein said means for directing waste combustion gases through saidinlet into said chamber includes a muffler through which said gases passprior to passage through said inlet and wherein said spray means forspraying water into said gases is located so as to spray water into saidgases prior to their passage through said muffler.
 19. Apparatusaccording to claim 17 which comprises drain means for draining from saidcollection container free water collected in said container, waterrecycling means comprising a return line for directing water from saiddrain means through said return line to said spray means, and a pump forpumping water removed from said collection container by said drain meansto said spray means.
 20. Apparatus for purifying waste combustion gaseswhich comprises elongated conduit means, a refrigerating unit fordirecting a refrigerant through said conduit means at a temperaturesufficiently low to form ice on the surface thereof by the condensationand freezing thereon of moisture contained in gases in contacttherewith, an ice contact chamber in the form of an elongated passagehaving an inlet and an outlet spaced from said inlet the inner surfaceof which is in proximate spaced relation with respect to the externalsurface of said elongated conduit means for extended travel of gasestherethrough in contact with the external surface of said elongatedconduit means, means for directing waste combustion gases into the inletof said elongated passage for passage therethrough to said outlet, asuccession of baffles within said passage which impart turbulence tosaid gases during their travel therethrough in contact with the externalsurface of said elongated conduit means, channel means comprises in saidpassage and disposed underneath said elongated conduit means for thereception of liquid and particulate accumulations released from thesurface of said elongated conduit means, said channel means beingadapted for the travel of said liquid and particulate accumulationsreceived therein in the direction of travel of gases passing throughsaid passage for discharge with said gases from the outlet of saidpassage, a collection container for said accumulations having an inletand an outlet, conduit means connected betweeen said chamber and saidcontainer which is disposed to direct waste gases and said accumulationsemerging from said outlet of said passage into said collection containerthrough said inlet thereof, said collection container includingseparating means for the retention of said accumulations therein whilepermitting travel of waste gases therethrough from said inlet to saidoutlet of said collection container for discharge therefrom. 21.Apparatus according to claim 20 wherein said elongated conduit means andsaid passage comprised in said ice contact chamber are respectively incoil form having a plurality of reaches disposed approximatelyhorizontally.
 22. Apparatus according to claim 21 wherein said elongatedconduit means is disposed substantially concentrically within saidpassage and whErein said baffles extend partially across said passagewith the inner margin substantially vertically disposed and cut away toaccommodate a portion of the external surface of said elongated conduitmeans, said baffles being disposed on opposite sides of said elongateeconduit means in staggered relation to provide support for said conduitmeans and leaving substantially unobstructed said channel means so as topermit travel of said liquid and particulate accumulations along saidchannel means to said outlet of the said passage comprises in said icecontact chamber.
 23. Apparatus according to claim 20 wherein saidcollection container comprises an elongated passage for the travel ofgases from said inlet to said outlet of said collection container, areceptacle for liquid and particulate accumulations disposed underneathsaid elongated passage, an elongated conduit means the external surfaceof which is in proximate spaced relation with respect to the innersurface of said passage in said collection container, and refrigeratingmeans for directing a refrigerant through said elongated conduit meansat a temperature sufficiently low to condense water vapor on saidexternal surface thereof and convert it to ice.
 24. Apparatus accordingto claim 23 wherein said elongated conduit means in said passage in saidcollection container is an extension of the elongated conduit meanswithin the passage comprised in said ice contact chamber.
 25. Apparatusaccording to claim 24, which also comprises a container for a liquifiedgaseous material having a sufficiently low temperature and valvecontrolled means for injecting said liquified gaseous material from saidcontainer into said ice contact chamber, whereby on starting there is arapid chilling of the ice contact chamber so as to produce ice thereinsubstantially immediately.
 26. Apparatus according to claim 25 whichcomprises an engine starting switch and means for actuating said valvecontrolled means responsive to actuation of said engine starting switch.